What 2 eukaryotic Nuclear division mechanisms lead the distribution of DNA nuclei in forthcoming daughter cells?
mitosis & meiosis
Mitosis is used by multicelled organisms ____, ____, _____
3)asexual reproduction by repeated divisions of somatic cells
Meiosis occurs only in particular somatic cells, called ______
germ cells (germ line cells).
They divide to form gametes
meiosis & cytokinesis to produce_____
____ & _____ produce gamates
meiosis & cytokinesis
* important in sculpture
is also the region where the duplicated
chromosome will attach to the microtubules of the spindle during nuclear division
human somatic cells contain ___ chromosomes
46 (23 pairs)
do species have the same # of chroms?
complex of proteins associated with the centromere of a chromosome during cell division, to which the microtubules of the spindle attach.
(disk) between chrom couple
Define spindle fibers
form a protein structure that divides the genetic material in a cell.
necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division:
Homologous chromosomes vs sister chroms
Sister are attachable “x” (single)
If not attached “single”= homologus (couple)
Somatic cells are diploid or haploid
Dip (2 of each type)
Gametes (egg and sperm) are diploid or haploid
Haploid (only single chrome of each)
Most of a cell’s existence (about 90 percent) is spent in ___ & the smallest is in ______
Interphase & mitosis
Cytoplasmic componetnts double & the DNA is duplicated
Interphase G1 is where
most of the carbohydrates, lipids, and proteins for a cell's own use and for export assembled. (cell growth b4 dna duplicated)
(begins in daughter cells)
Interphase s, is where
the cell copies its _dna_ and synthesizes proteins used in organizing the condensed chromosomes.
(when chrom duplicated then dna is too)
Interphase g2 is where
the proteins that will drive mitosis to completion are produced.
(dna duplicated, cell preps for division)
ends in parent cell)
The four sequential stages of mitosis are:
prophase, metaphase, anaphase, and telophase.
The spindle apparatus moves the chromosomes.
1.The spindle apparatus is composed of two sets of microtubules.
2. Microtubules (components of the cytoskeleton) extend from the two "poles" of the cell and overlap at the cell equator.
1.Chromosomes become visible as rodlike units, eachconsisting of two sister chromatids.
2. By late prophase, each chromatid has a constricted region called the centromere, on the surface of which is the kinetochore, docking site for the spindle microtubules.
3.In the cytoplasm, the microtubules of the cytoskeleton break apart and begin reassembling near the nucleus.
4.The nuclear envelope begins to _disintegrate_.
5. The centrioles, which have duplicated by the time prophase is underway, are now moved by the microtubules to the opposite poles of the cell.
Transition to metaphase (4 + 1)
*spindle apparatus forms
1. The nuclear membrane now breaks up
2. Sister chromatids go toward opposite poles.
3. all chromosomes lined up in middle are called metaphase.
4.At metaphase sister chromatids are at max. condensation
From Anaphase Through Telophase 2)
1.Sister chromatids separate and move toward opposite poles.
2. Telophase begins when the two daughter chromosomesof each original chromatid pair arrive at opposite poles.
Cell Plate Formation in
rigid cell wall, the cytoplasm of plant cells cannot just be pinched in two.
Gametes are diploid or haploid
Gametes are diploid or haploid
G1 takes ___ hrs
s phase (interphase) takes___ hrs
10+hr (the longest)
G2 takes ___ hrs
mitosis takes __ hrs
weither a cell is going through mitosis or miosis its mandatory for it to go to interphase first T/F
Meiosis begins with diploid (__n = ___ in humans)
(2n = 46 in humans)
2n are 2 chroms of each type called
Homologous chromosomes line up (even unequally or equally matched sex chromosomes!) during meiosis.
Meiosis produces gametes that have ___ of each pair of homologous chromosomes.
Unlike mitosis, meiosis has __ series of divisions;
2 (both meiosis I and II.)
meiosis I, homologous chromosomes pair and cytokinesis follows. (2)
1) Each of the two daughter cells receives a haploid
number of chromosomes.
2) Each chromosome is still duplicated.
What are the 2 nuclear division mechanisms?
what are the 2 cytoplasmic division mechanism:
1- cell plate form
In meiosis II, the sister chromatids of each chrom ___, cytokinesis follows resulting¬¬¬¬ in ___ haploid cells
separate; & four
End of mitosis ends with -_________
2 diploid cells
what goes on in prophase 1
-homo chroms pair up
-alleles for the same trait can vary, new combinations of genes in each chromosome can result
-non sister chroms cross over (not about the # of cross overs), after they don’t look identical
what goes on in Late prophase?
-nuclear envelop starts to break down
-sis chrom starts to condense (thicker& shorter) (coiling)
what happens in metaphase 1
homo chroms go random in equator
what happens in anaphase 1?
homologous chromosomes (still duplicated) separate into two haploid cells each of
which has a random mix of maternal and paternal
what happens in anaphase 2?
Sister chroms seperate
Gamete Formation in Animals
meiosis to gamete formation >>> fertilization >>> growth by mitosis.
In males, meiosis and gamete formation are called
In male meiosis 1 there are 2 spermatocyte while the end of meiosis 2 result in
female germ cell starts with 2n and ends with # after mitosis 2
one large ovum (n) plus three polar bodies (n, small).
Spermatids change in form; each develops a tail to become
In females, meiosis and gamete formation are called
The _____ovum is the only cell capable of being fertilized by a sperm; the polar bodies wither and die
The variation present at fertilization is from three sources
1.cross over from prophase 1
2.random alignments at metaphase 1
3.fertilization, divers gametes are produced
2 similarities Meiosis & Cytokinesis and Mitosis & Cytokinesis Compared
1. interphase for both.
a.duplicates its DNA
b.Each duplicated chromosome consists of two sister chromatids linked at the centromere.
2.Microtubules of the spindle apparatus move the chromosomes in prescribed directions in both procedures.
Differences between Meiosis & Cytokinesis and Mitosis & Cytokinesis
Prokaryotes usually reproduce by
Genetic variation in prokaryotes can result directly through (3)
transduction or transformation. (indirect)
In many species, daughter cells also inherit one or more plasmids.
1. A plasmid is a small, self-replicating circle of DNA with a few genes.
2. Usually these genes confer a survival advantage such as resistance to antibiotics.
3. Some of the plasmid genes give instructions to engage in prokaryotic conjugation.
4. Prokaryotic conjugation is a mechanism by which a copy of a plasmid is transferred from a donor bacteria to a recipient bacteria.
Who is the father of genetics?
Diploid cells have ____________for each
trait, each on a homologous chromosome.
a pair of alleles
True-breeding lineage occurs when
offspring inherit identical alleles, generation after generation;
non-identical alleles producehybrid offspring.
When both alleles are the same, the condition is called
the homozygous condition;
if the alleles differ, then it is the heterozygous condition
When heterozygous, one allele is _____ (A), the other is ____(a).
dominant & recessive
Homozygous dominant =,
homozygous recessive =
, and heterozygous =
Genotype is _____________, and phenotype are_____________
the sum of the alleles
traits based on the genotype and the environmental factors.
1. the meaning of complete dominance
2. segregation of homo alleles
3. test crossing
whats the ratio for F2 generation in geno & phenotype
Geno ratio goes from left corner across down to the right ex1:2:1 = chances (totaling 4) ¼: 2/4: 1/4
phenol is more on the # of results X the underdog ex: 3:1
Whats the Mendel's Theory of Segregation
2n organisms inherit two alleles per trait located on pairs of homologous chromosomes.
What the Theory in Modern Form
During meiosis the two alleles segregate from each other such that each gamete will receive only one allele/trait
what are Independent assortment alleles
for 2 diff traits in gamet, random alignment in metaphase 1
The 9:3:3:1 is the result of a dihybrid cross between two heterozygous parents.This means that you're mapping out a cross while observing two alleles. Instead of observing the genotypes, however, you are observing the phenotypes. This means that the 9:3:3:1 ratio is categorizing based on how the organisms look, not according to their letter combinations.
whats incomplete dominance
a dominant allele cannot completely mask the expression of another.
Ex: red + white = pink
both dominant alleles are expressed in heterozygotes(for example, humans with both glycolipids designated with blood type AB
whats multiple allele system
Whenever more than two forms of alleles exist at a give locus,
pleiotrophy: multiple effects of single genes
allele produces multiple affects : 2 or more traits
ex: sick cell anemia
whats sick cell anemia
impaired oxyegen flow damages tissues
hemoglobin- clump red blood cells
epistasis: interactions between gene pairs
one pair influences other pairs combined activities producing some effect on phenotype
ex: cancer, hair color in mamals
fat can increase undesirable traits
such as cancer
chromes same quantity & type of both sexes ( 44 in humans + 2 sex chrome)
2 in humans determine gender
located on Y chrome
production of testacies
Carries for sexual traits & non sexual traits
Mutated but it doesn’t involve medical. Not life threating
Involve medical problems & are deadly
How they become: Mutated genes & changes in chrome #s
Autosomal recessive ( what is affected)if a is the mutated gene vs A being mutated: aa, Aa, AA
aa- yes recessive // dom no
Aa- no but masked// dom yes (not strong enough to mask)
AA- no/// dom yes (lethal)
Cystic fibrosis – (inherited) Recessive alleles
Brings sticky mucus clog organs like lungs and pancreas
Degeneration of nervous system
Dominate doesn’t matter when it gets the gene it will get the diseases
High cholesterol in blood
Environmental factors matter
Epithelial Tissue (3)
Made up of squamous, cuboidal,columnar
Stratified epithelium consists of
two or more layers of cells; example: skin.
Connective Tissues are made of (7)
Soft Connective Tissues
Dense connective tissue
. Bone tissue
Soft Connective Tissues
Loose connective tissue
Organs and surrounds blood vessels and nerves;
Dense connective tissue
could be found in tendons (muscle to bone) and ligaments (bone to bone)
Locations include the ends of bones, parts of the nose, external ear, and disks between vertebrae.
stores mineral salts, produces blood cells, and provides spaces for its own living osteocytes
the storage of fat, which can be used as an energy reserve and as cushions to pad organs.
transports oxygen, wastes, hormones, and enzymes
Muscle tissue (3)
Skeletal- attaches to bones
Smooth- lines the gut, blood vessels, and glands ( involuntary)
Nervous tissue (2)
Central Nervous System
Peripheral Nervous System
Homeostatic control mechanisms require three components: (3)
a. Sensory receptors detect specific changes in the
b. Integrators (brain and spinal cord) act to direct impulses
to the place where a response can be made.
c. Effectors (muscles and glands) perform the
Negative vs positive feedback
Negative detecting a change in theinternal environment that brings about a response
Positive intensify the original signal; childbirth is an example